72 URINARY ORGANS. 



and backwards, and the broad end of the ovoid is above. Its 

 periphery is smooth, so that one does not infer from an external 

 examination, the lobules or internal divisions. The excavation 

 of the kidney, called its fissure, (hilum renale) occupies about 

 one third of its long diameter, is bevelled in front, and leads to 

 the very interior of the gland; conducting its blood vessels and 

 excretory duct, which have to pass through a quantity of cellular 

 and adipose matter. The kidneys are generally of equal size, 

 being about four inches long, and two wide; and each one weighs 

 three or four ounces. They have no ligaments for keeping 

 them in position, but depend for the latter upon the adjacent 

 cellular adhesions and blood vessels. 



The kidney being destitute of a peritoneal coat, has a well 

 marked capsule which envelops it entirely and penetrates into 

 its fissure for some depth, where it is perforated with foramina 

 for transmitting the blood vessels and the ureter. This capsule 

 is white, semi-transparent, fibrous, strong, and elastic: it adheres 

 to the surface of the kidney by delicate cellular and vascular 

 filaments, which are so weak that they permit it to be stripped 

 off without difficulty, and when so removed, some indications 

 of the lobulated condition of the organ are seen. 



Of the Minute Structure of the Kidney. When the kidney is 

 cut open longitudinally, it obviously consists of two kinds of 

 substance, differing in their situations, colour, consistence, and 

 texture. The one making the periphery of the gland is called 

 from its position Cortical, (Substantia Corticalis, Glandulosa,) 

 while the other, being more internal, is designated as the 

 Medullary or Tubular, (Substanlia Meduttaris; Tubulosa; Fi- 

 brosa.) 



The Cortical or Secretory Substance forms the whole cir- 

 cumference of the kidney, and, on an average, is about two 

 lines in thickness; but it is thicker at some points, as, from its 

 internal face, processes converge towards the centre of the 

 gland, which separate the tubular part into as many distinct 

 portions of a conoidal shape. It js composed principally of 

 arteries and veins ramifying, among small graniform cor- 

 puscles that secrete the urine, and are very distinct when 

 viewed with a microscope. It tears with facility, thereby pre- 



